In general, a capacitance-type touch panel is a position input device which senses a change in capacitance between a human fingertip and a conductive layer to detect a position of the fingertip, and as capacitance-type touch panel, there exists a surface type and a projection type. The surface type one has a simple constitution; however, it is difficult to detect two or more contacts simultaneously (multi-touch). Meanwhile, the projection type one is composed of multiple electrodes arranged in a matrix, and more specifically, it has a constitution that a plurality of first electrodes are arranged in a horizontal direction and a plurality of second electrodes are arranged in its perpendicular direction via an insulating layer, and is able to detect a multi-touch by sequentially sensing a capacitance change in the first electrode group and the second electrode group.
Though a touch panel like this is mainly applied to a small size one for a smartphone or a tablet device, it is considered in future to proceed enlargement in size for an application to a display for a personal computer or the like. In this future trends, since a conventional electrode is made of ITO (indium tin oxide), its resistance is high (about hundreds ohms/sq.), and so there is a problem that transfer rate of current between electrodes reduces and response speed (time from contact with a fingertip until detecting its position) is delayed as its applicable size increases. In addition, since ITO is expensive, it has been a problem of difficulty of the enlargement.
Therefore, in order to solve these problems, a technology for constituting an electrode of a metal fine line (that is so called a metal mesh electrode), that is formed by microfabricating a metal thin film of inexpensive and low resistance gold, silver, copper or the like and has a line width invisible to a touch user, has been developed. Touch panels using a metal fine line for the electrode are known in the Patent Literatures 1 to 3, for example.